Desulfurization of hydrocarbon oils



Jan. 3, 1956 R. B. BISHOP ETAL 2,729,590

DESULFURIZATION. oF HYDRocARBoN ons MSM/17H? /IIR 35 37 35 3' 59 g.. im?.

HTTONE Y r Jan- 3, 1956 R. B. Bisi-QP :TAL

DESULFURIZATION OF HYDROCARBON OILS 2 Sheets-Sheet 2 Filed Jan. 2, 1953 aww 0 @H0/www M United l States Patent DESULFURIZATION 0F HYDROCARBON OILS Richard B. Bishop, Haddonleld, William I. Denton, Woodbury, and William E. Garwood, Haddoufield, N. J., assignors to Socony Mobil Oil Company, Inc., a corporation of New York Application January 2, 1953, Serial No. 329,292

14 Claims. (Cl. 196-27) This invention relates to a selective desulfurizing process and, more particularly, to an improved method for conducting desulfurization of hydrocarbon oils. In a more specific sense, the invention contemplates the treatment of sulfur-containing petroleum oils and various liquid fractions obtainable therefrom with a reagent capable of selectively removing sulfur.

In the refining of petroleum and fractions thereof, the presence of sulfur and sulfur compounds has universally been recognized as undesirable. Petroleum hydrocarbons generally contain varying amounts of sulfur compounds as impurities. Among the sulfur compounds may be mentioned hydrogen sulfide, mercaptans, alkyl sulides, dialkyl sultides, thiophanes and thiophenes, which are distributed in the various fractions and products obtained from the crude hydrocarbon stocks according to their boiling points or to their relative volatility in hydrocarbon mixtures. Also, the particular kind and amounts of said sulfur compounds present in a petroleum hydrocarbon vary with the previous manufacturing and processing operations to which said petroleum hydrocarbon has been subjected. Thus, as an example, straight run gasolines generally contain non-refractory type sulfur compounds, notably hydrogen sulfide, mercaptans, disuliides, and, to a lesser extent, aliphatic suldes together with some refractory type sulfur compounds, including cyclic ring compounds, of which the thiophanes and thiophenes are typical examples. Some straight run gasolines contain non-refractory type sulfur compounds and therefore can be relatively easily desulfurized by conventional methods. Certain gas oils, crudes, and cracked gasolines, on the other hand, contain appreciably greater amounts of the refractory type sulfur compounds, which are difficult to remove, and it has been reported that cracking operations have a tendency to convert the non-refractory open chain sulfur compounds and hydrogen sulfide into the refractory cyclic compounds.

All of the foregoing sulfur compounds are objectionable in hydrocarbon oils because of their bad odor and corrosive tendencies. Their presence in gasoline fractions reduces the effectiveness of tetraethyl lead. The non-refractory sulfur compounds can be altered to less objectionable form or removed by a number of conventional treating operations, such as catalytic decomposition in the vapor phase, treatment with acid, adsorption 2 in the liquid phase with silica gel or bauxite, oxidation with doctor solution, and processing with caustic tannin.

Refractory sulfur compounds, however, are not satisfactorily removed by any of the foregoing methods. Since it is generally essential to effect removal of substantially all sulfur from petroleum fractions, particularly those intended for motor fuels, considerable attention has been given in the past to certain catalytic hydrogenation procedures which are capable of removing all of the various type sulfur compounds, including refractory sulfur compounds from petroleum hydrocarbons. These procedures are carried out by contacting the hydrocarbon charge with hydrogen in the presence of a sulfur-resistant hydrogenation catalyst at elevated temperature and pressure, whereby organic sulfur compounds present in the hydrocarbon charge are hydrogenated to form hydrogen sulfide, which can readily be removed4 from the treated hydrocarbons. Such procedures generally involve a considerable consumption of hydrogen, and the cost of supplying the hydrogen is an important factor inuencing the economics of the process. `In addition, in order to secure the required partial pressure of hydrogen, it has generally been essential to operate at elevated pressures of 1000 p. s. i. or greater, necessitating the use of relatively expensive special steels in plant construction which, in turn, imposes a further economic burden on the process.

It is a major object of the present invention to provide a method for removing sulfur compounds, including those of a refractory nature, from petroleum hydrocarbon oils without encountering the difficulties inherent in the aforementioned prior art procedures. A further object is the provision of a process for effecting selective desulfurization of hydrocarbon oils wherein the sulfur content thereof is effectively reduced without adversely influencing the yield and quality of the resulting desulfurized product. A still further object is the development of a commercially attractive desulfurization method for treating sulfur-containing hydrocarbon oils capable of continuous operation.

These and other objects which will be apparent to those skilled in the art are achieved in accordance with the present invention. Broadly, the process described herein involves treating hydrocarbon oils containing refractory and/or non-refractory sulfur compounds With hydrogen iodide, iodine, or a hydrogen iodide-iodine mixture at a moderately elevated temperature below that at which appreciable cracking of the hydrocarbon charge stock to lighter material is encountered.

It has been discovered, in accordance with the present invention, that iodine, hydrogen iodide, and mixtures thereof under particularly defined reaction conditions hereinafter set forth provide a highly efficient and selective means for effecting removal of sulfur from hydrocarbon oils containing the same. It is contemplated that sulfur-containing hydrocarbon oils generally may be treated in accordance with the instant process. Thus, pe-

troleum crudes, gas oil, gasolinas, and reduced crudes i containing sulfur have been effectively treated with resulting desulfuri'z'ation thereof. The process is most effective in treatment of the lighter stocks and is particularly applicable in treating stocks which contain refractory type sulfur compounds not easily removed by conventional desulfurization processes, such as stocks derived from Trinidad, California, Vand Mexican crudes. In addition to removal of sulfur, oxygen is also removed from hydrocarbon stocks undergoing the treatment described herein.

The process of the invention involves contacting a'sul fur-containing hydrocarbon stock with hydrogen iodide, iodine, or a hydrogen iodide-iodine mixture under hereinafter defined reaction conditions. The products resulting from the treatment comprise gases, the desulfurized liquid hydrocarbon product, and a tarry precipitate. The desulfurized liquid hydrocarbon product normally contains a small amount ofv HI or iodine which can be removed by water-washing. A caustic wash is desirable to ensure complete removal of HI or iodine from the hydrocarbon and also to scrub out any H28 or light mercaptan-and.r thus improve the odor. A substantial proportion of the Hl charged may be recovered by extractthe tarry precipitate with water and the extract may be recycled for further use in desulfurization. Remaining iodine, elemental and/or combined, may be recovered from the waterfwashed tarry precipitate by burning at lan elevated temperature. The iodine so recovered may likewise be employed in effecting further desulfurization. The gaseous reaction product contains a substantial proportion of light hydrocarbons and may, after water-washthrough conduit 13. The contents of the reactor are then heated under the desired conditions of temperature, pressure, .and time hereinafter specified. The products` resultingfrom this treatment consist of a mixture of hydrogen andV light hydrocarbon gases, desulfurized liquid hydrocarbon stock, and a tarry precipitate. After the aforementioned heat treatment, the gaseous products are removed from the reactor through outlet pipe 14, the rate of tlow being controlled by valve 15. After the gaseous products have been withdrawn, the liquid content Vof the reactor is removed through outlet vconduit 16 upon opening valve 17 and passes into settling tank 18. The liquid product consists of an aqueous layer and an overlying oil layer. The oill layer is withdrawn from the settling tank able combustion supporting gas is led into the furnace through conduit 34 and iodine is removed from'the tar by burning at an elevated temperature. iodine fumes pass through outlet conduit 35 and through a series of scrubbers 36 containing water, in which iodine is precipitated and collected on screens 37. The scrubbers are interconnected' by pipes 38 and the water may be withdrawn therefrom through outlet conduit 39. The iodine collecting on the trays in scrubbers 36 is removed at intervals and may be employed in preparing aqueous Hi solution for further desulfurization activity or the iodine itself may be used for accomplishing desulfurization upon bringing the` same into contact with Vthe hydrocarbon stock under the reaction conditions of the inven-V tion.

The method of the invention must be carried out under speciiic operating conditions in order to'effect removal of the sulfur without detrimentally aiectingthe yield of desired desulfurized product. Thus, it has been found that the temperature 0f the instant process must be maintained within the approximate range of 550 toV 850 F. Below about 550 F., substantially no desulfurization takes place, while, at temperatures in excess of 850 F., appreciable cracking of they hydrocarbon stock takes place, resulting in distinctly lower liquid recovery and higher gas-make with little additional desulfurization.

Figure 2 of the attached drawing illustrates this finding graphically and the eifect of temperature is shown on the extent of ,sulfur removal and the volume yield of treated liquid product on contacting a hydrocarbon charge ofl light gas oil initially containing 1.39 per Vcent sulfur with an aqueous solution of HI under reaction conditions where the reaction time was 2 hours, an approximately 50 per cent aqueous HI solution was employed, and the ratio of l/S, i. e., the ratio of gram atoms of iodine to gram atoms of sulfur contained in the charge stock, was

Y 2.3. An examination of this figure shows that, under through outlet conduit 19 and passes into a wash tank 20, wherein it is washed free of HI with water introduced through'conduit 2l. The Washed desulfurized oil product is withdrawnthrough outlet conduit 22 and the wash water containing soluble matter is withdrawn through outlet conduit 23.

V2.4 in reactor 10 and is withdrawn from the reactor through a trap door 25 in the reactor wall. The tarry precipitate passes from the reactor through said outlet into a wash vessel 26. Water is led into vessel 26 through conduit 27 andthe water containing extracted Hi is withdrawn through outlet' 28 and forced through conduit 29 by means of a pump, not shown, to storage tank 12. The aqueous layer in settling tank 18 containing dissolved Hl is withdrawn from the bottom of the tank through outlet conduit 30 and is likewise recycled along with the aqueous tar extract through conduit 29 to storage tank 12. The tarry precipitate in vessel 26, after aqueous extraction thereof, iswithdrawn upon opening valve 31 and passes through conduit 32 into a furnace 33. Air or other suitthe aforementioned contacting conditions, the minimum reaction temperature for accomplishing desulfurization was about 550 F. and thatthe extent of desulfurization thereafter rapidly increased with a rise in temperature until about 750 F. was reached with a slight reduction in t yield of desired product. In the range of 750 F. to 850 F., the amount of desulfurization increased, but at a` much lower Vrate and with rapid decline in product yield. Above about 850 F., no further substantial desulfurization was accomplished and the yield of liquid product, due to cracking, greatly decreased. The preferred temperature range forY operation of the instant process is accordingly between about 650 F; and about 750 F. lt is to be understood, however, that a minimum operating temperature of about 550 F. is a critical feature of the present process.

Figure 3 of the drawing shows theeifect of reaction time on the extent of sulfur removal using the aboveidentified stock, a temperature of 700 F. and a 50.5 per cent aqueous HIrsolution and an I/S ratio of 2.3. From an examination of this figure, it will be seen that an increase in reaction time Vincreased lthe extent of sulfur Y removal rapidly up to about 2 hours, at which time desulfurization hadV approached a maximum, slight additional desulfurization occurring up to about 7 hours, after which substantially no further desulfurization was accomplished. While excessively long reaction times should vbe avoided to avoid degradation of the stock, it is contemplated that ar reaction time up to about l0 hours may beV employed if desirable or necessary. While some desul-V furization is accomplished using a very small residence time as low as .0l hour, the optimum desulfurization is btaned, as will be noted from Figure 3at between about Y2 and about Shouts.

Figure 4 of the attached drawing shows the effect of The released I/S ratio on the extent of desulfurzation using the same stock and reaction conditions as reported for Figure 2, with the exception that a reaction time of about 2 hours and a varying I/S ratio was employed. The I/S ratio represents the ratio of gram atoms of iodine present in the HI or iodine reagent used to the gram atoms of sulfur present in the hydrocarbon stock undergoing treatment. From an examination of this treatment, it will be seen that more desulfurization occurred with higher I/ S ratios but with less efficient use of the reagent. Thus, it will be noted that an increase in the I/S ratio increased the extent of sulfur removal rapidly up to an I/S ratio of about 1. Thereafter, with increasing I/S ratios, the extent of desulfurization proceeded, but at a much slower rate. Ratios of 0.1 to 2.5 are operable; a ratio of less than about 0.1 reduces the total sulfur to a minor extent, while little additional desulfurization is obtained by increasing the ratio above 2.5. Generally, an I/S ratio of between about 0.6 and about 2.4 is preferred for use in the present process.

Figure 5 of the attached drawing shows the effect of concentration of HI in Water on desulfurization, using a fixed I/S ratio of 2.3, a reaction time of 2 hours, and a temperature of 700 F. on the above-identified hydrocarbon stock. From an examination of this figure, it will be noted that the degree of desulfurization varied directly with the concentration of HI in water. Thus, approximately twice as much desulfurization was obtained with a 50 per cent Hl solution as compared with a 25 per cent HI solution in water. Without being limited by any theory, it is believed that this phenomena is due to a lower concentration of HI in the hydrocarbon phase when more water is present since the HI is more soluble in water than in oil. i

The agent employed herein in effecting desulfurization may be either iodine, hydrogen iodide, or a mixture of iodine and hydrogen iodide. The reagent may be employed in dry form or in the form of a solution in a suitable solvent. Thus, HI is conveniently employed in the form of an aqueous solution but also may be used in a solution of a low molecular weight alcohol or other solvent. Likewise, iodine may be used in the form of a solution in an alcohol or other suitable solvent. As a general rule, iodine will desulfurize more effectively under given conditions than HI but at a somewhat lower yield level. The desulfurization activity of iodine and the yield level of aqueous Hl may be obtained by combining a concentrated solution of iodine in aqueous HI, for example, a solution of 40 to 60 wt. per cent iodine in 55 per cent aqueous HI. The hydrocarbon stock may also be desulfurized with the tarry precipitate which is formed during the reaction and which contains elemental iodine. It has been found that this tar possesses the ability to desulfurize hydrocarbon stock and that re-use of the tar containing iodine appreciably decreases the amount of fresh make-up iodine or hydrogen iodide required. With the use of aqueous hydrogen iodide as the treating reagent, A

it was found that the presence of a small amount of red :phosphorus promoted the reaction so that a much lower I/S ratio may be employed for a predetermined extent of desulfurization as compared with the I/S ratio used in the absence of red phosphorus. The presence of hydrogen in the reaction mixture was found to increase liquid recovery and to increase the extent of desulfurizetion. Accordingly, the presence of hydrogen in an amount `'sufficient to maintain the hydrocarbon oil in liquid phase and generally between about 100 and about 3000 p. s. i. g. pressure effects a decrease in the amount of HI or iodine required.

The desulfurization obtained with the use of iodine, hydrogen iodide or mixtures thereof in accordance with the present process is unique in comparison with the treatment of sulfur-containing hydrocarbon stocks with the other halogens, or hydrogen halides. Thus, in cornparable runs, aqueous HB1' desulfurized a hydrocarbon stock 9 per cent and aqueous HC1, 28 per cent, under conditions at which aqueous HI desulfurized the identical stock 73 per cent. The process described herein affords a method in which the HI or iodine combines selectively with sulfur and oxygen compounds with resultant high yields of liquid products. In contrast to the present process, treatment of sulfur-containing stocks with HF, for example, throws out asphaltic materials which are higher in sulfur content than the balance of the stock and thus desulfurizes only in proportion to the amount of asphalt and sulfur content of the asphalt. Accordingly, with HF, poor yields and poor selectivity result while treatment with hydrogen iodide or iodine in accordance with the instant process affords high yields and good selectivity.

The following examples will serve to illustrate the process of the invention without limiting the same:

Example 1 F Initial boiling point 50% 521 End point 652 and an aqueous solution of 55 per cent by weight of hydrogen iodide was added to the bomb in the amount of 41 grams. The head of the bomb was secured and the bomb pressured to 1000 p. s. i. g. with nitrogen to test for leaks. After venting to atmospheric pressure, the bomb was closed, heat was applied, and the temperature held at 700 F. for 2 hours, maximum pressure being 950 p. s. i. g. At the end of this period, the heat was turned oif and the bomb was allowed to cool to room temperature. Gaseous products in the amount of 0.28 mole were vented and were determined by mass spectrographic analysis to have the following composition:

Mole per cent Hydrogen 36.4 Methane 34.8 Czs 14.4 Cas 6.5 C4s 2.5 C5s 0.9

The head was removed from the bomb :and 167 grams of liquid product, consisting of 6 cc. of aqueous layer and 184 cc. of oil layer were decanted. The oil layer was extracted three times with 250 cc. portions of water to remove iodide therefrom. The rainate (182 cc.), after drying, analyzed as follows:

Specific gravity 0.8649 Bromine number 11.1 Vol. per cent arornatics4 40.0 Per cent sulfur 0.38

TABLE l Y Values For., Reaction Conditions Liquid Hydrocarbon Product Liquid Hydro- Aqueous carbon product; s1 k EX Las? C fr 1 im ample HI Pm Bw v01. W, sands, v01. Percent Stock, Temp., Time, Sure ce Specific mine percent ement Grams percent Reducoo. Ratio F. Hrs. s i Gravity No Aropum Recovtion InA Grains IIS p' 'g' matics ery Sulfur l 0. 7711 88 23 1. 13 CflllfonllaBCgkellzSalo 2 200 25 1. 07 555 1 5 2, 500V 1.84 o. 7s09 s 24' 0.59 2s 92.0 4s .1519( '2671. 'F 3 200 25 1.97 700 2 075 les 0.7694 s 25 0.085 37 s4. o o3V 'ltgop en 4 20o 25 1.97 700 2 L5,000 1180 0.7752 5 2e 0.25 3o 90.0 7e p01 J1 5 250 s oas sro n 1,200 2 22s 0. 7699 15 2s 0. 35 7 00.5 e9 Middle East Atmosl pheric gas oil (I. B. P. 0.8433 9 18 1.28 456 F., 50% 544 F., 6 200 36 2 700 2 S00 i90 0. 8383 0 10 0. 70 37 95.0 38 end point 644 F.) Ng. Zotlelgglyll 44 0 5t end point 658e 7 200 22 2 26 700 2 10J 184 28 g2' 0 36 California Crude Oil 1 (I. B. P. 170 F., 50% 8 200 36 2 26 700 2 950 178 56 89.0 77 695 F.ora0kiug). 9 600 l 7. 5 4 0 b5 700 2 275 530 88. 0 41 California Residuuru (311% of crude-I. B. P. 515 F., 50% 940 l0 200 8l. 2 88 700 2 700 195 81 97.5 2l F., 75% 1,100 F.)

1 Percent oxygen=0.05, as compared to 0.58 for original gasoline. 2 Percent oxygen=0.09.

2 Plus 12.5 g. iodine.

4 Ratio (HI-HNS.

5 Initial pressure 1,000 p. s. i. nitrogen.

Initial pressure 1,500 p. s. i. nitrogen.

It is to be Vnoted from the above examples that the process of the invention is broadly applicable in desulfurzing a variety of petroleum stocks with high volume f per cent recovery. The process is further effective in removing oxygen from hydrocarbon stocks, as will be evident from Examples 4 and 5, wherein the oxygen content was reduced from 0.58 per cent to0.05 and 0.09 per cent,

respectively. This represents a per cent reduction in oxyof a small amount of red phosphorus in the reaction mixture:

Example 13 Two hundred ce. of. a` light gas oil,v having the properties set forth in Example 1, were contactedwith one gram oran aqueous solution of per cent by weight hydrogen'l iodide and 2 grams or" red phosphorus in a rocking type bomb. The bomb was closed and the temperature raised to approximately 700 F. and maintained at this temperature for about 2 hours. The pressure attained wasfl'ess than 100 p. s. i. g. At'the end of the reaction time, ythe heat was turned off and the bomb was allowed to cool Y to roomrtemperature. A liquid hydrocarbon product in. the amount of 187 grams was obtained having a sulfur content of 1.03 per cent.

TABLE Il Reaction Conditions Liquid Hydrocarbon Product Values For Liquid Bl y d r o c a r b o n AqueousA Product Aqueous HI Layer Example Gas Bm Vol. Wt and v ou Ratio, Temp., Time, PressureY cc Specific mine Percent Percp'nt Solids, V01 Percent c Conan., I/S F. Hrs. p. s. i. g. Gravity N Aro- S 1f r Grams P t Reduc C 'Y Wt. Grams O' matics u u Relcsl tion in.- Percent v y Sulfur 200 50. 5 45 2. 31 700 2 1,050 185 0. 8681 11 39 0. 45 44 92. 5 68 200 55 4l 2. 30 G90 2 2, 500 196 0. 8602 8 35 0. 39 30 Q8. 0- Y 72A cent recovery of liquidV hydrocarbon product-was 93.5

per cent. Av comparable'run in theabsence of addedredijl'losphorus,V employing the equivalent small I/Sratioiof.

0.05, as willbe evident from an examination of Figure 4, affords only about 5 per cent removal of sulfur.

The eiect of iodine and mixtures ofHI and iodine 4on the extent of desulfurization of the gasoil defined in Example 1 is shown in the examples set forth. in the following table:

The reductionin sulfur was., accordingly 26 Vper cent by` weight and the volume Vper TABLE III t ValuestorLlquld Reaction Conditions Liquid Hydrocarbon Product Hydrocarbon Product Aqueous Layer Example Aqueous HI and Gas Br Vol. Wt Solid Vol. Percent 0 Added Ratio Temp., Time, Pressure c Specific mine Percent Percnt Grams Percent Reduccc Corien., 1:. a. I/S F. Hrs. p. s. l. g. c' Gravity No ro- Sulfur Recovtlon in wt. per- Grams matics ery Sulfur cent 41 0 2. 30 705 2 950 182 0. 8649 11 40 0. 38 59 01. 0 73 17 1 2. 30 095 2 1, 350 180 0. 8597 14 41 0. 19 53 90. 0 S5 0 19. 5 2. 00 702 2 300 170 0. 8654 12 63 0. 17 38 85. 0 88 2. 4. 2 1 0. 60 700 2 100 180 0. 8745 18. 4 37 0. 67 15 90. 0 50 1 Y) 0. 05 700 2 100 186 0. 8762 14. 9 39 0. 83 2l 93. 0 40 1 a) 0. 05 700 2 100 184 0. 8745 31. 7 29 0. 93 26 92. 0 33 1 Ratio (HH-ms.

2 15 g. tar from Ex. 17.

3 21 g. tar from Ex. 18.

It will be noted from the comparative results of Examples 14-17 that the desulfurization activity of iodine under given conditions is greater than aqueous HI but that a somewhat lower volume recovery is obtained. It is further to be noted from Examples 15 and 17 that the desulfurization activity of iodine and the yield level of aqueous HI may be obtained by using a concentrated solution of iodine in aqueous HI. Thus, in Example 15, a solution of 17 grams of iodine in 10 grams of 55 per cent aqueous HI elected 85 per cent desulfurization of the hydrocarbon charge at a 90 volume per cent yield, level, while, under the same conditions, treatment with iodine alone in Example 16 and treatment with 55 per cent aqueous HI alone in Example 14 gave 88 and 73 per cent desulfurization and 85 and 91 volume per cent yields, respectively. In Examples 18 and 19, the reagent used consisted of a small amount of aqueous HI in admixture with the tarry precipitate obtained from a previous run. As will be noted, use of the tarry precipitate aiorded a substantial reduction in sulfur content of the hydrocarbon charge stock.

As noted above, the use of iodine and hydrogen iodide under the conditions described herein effects a selective desulfurization of hydrocarbon oils. The extent of desulfurization with iodine and HI in accordance with the present process is much greater than corresponding treatment with other halogen halides. Comparative data showing treatment of the gas oil having the properties defined in Example 1 with HI, HBr, and HC1 under conditions wherein the ratio of halogen to sulfur is fixed are set forth in the following table:

F. in a closed vessel for 2 hours at a pressure of 1000 p. s. i. g. At the end of this time, gaseous products were vented and 190 cc. of a liquid hydrocarbon product having a sulfur content of 0.88 per cent by weight was obtained. The volume recovery was, accordingly, 95 per cent and the per cent reduction in sulfur was 37 per` cent.

The liquid product obtained in this example consisted of an aqueous layer which contained HI and a hydrocarbon layer. In addition to the gaseous and liquid products, a tarry precipitate was obtained which contained iodine and absorbed HI. The tarry precipitate was extracted with water and the resulting extract combined with the aqueous layer. The resulting combined mixture was found to contain 38 per cent by weight of the HI charged. The tarry precipitate, after extraction with water, contained 56 per cent by weight of the HI charged. This tar was heated in a current of air to recover iodine. The effluent gas was scrubbed in 3 successive water towers to precipitate iodine. Eighty-three per cent of the iodine in the tar was recovered at a maximum temperature of 650 F.

From the above example, it will be noted that a large proportion of the treating reagent used can be recovered. Such recovered hydrogen iodide and/or iodine may be used for eifecting further desulfurization.

It is to be understood that the above description is merely illustrative of preferred embodiments of the invention, of which many variations may be made within the scope of the following claims by those skilled in the art without departing from the spirit thereof.

TABLE IV Reaction Conditions Liquid Hydrocarbon -Product I Values For Liqcar on ro uc Aqueous Etydro- Example Gas gen Hahde '1` T' P Sp 'f Bw' am' t Wt riiiid v 1 e t em ime ressure ecirc ercen or s, o. creen 011 C Ratio Halogen/s F.p Hrs.' psig.y ce gravity lge Aro- Grams Percent Reducce. lllrrn., G m matics Ream tion in Percnt ra s ery Sulfur 200 HI 41 I/S 2. 3() 705 2 950 182 U. 8649 11 40 0. 33 59 91. 0 73 200 48 HBr 29. 6 13T/S 2. 28 700 2 625 184 0. 8816 1. 27 40 92. 0 9 200 38 HC1 17 CI/S 2. 30 700 2 550 183 0. 8762 12. 6 37 1. 0l 24 91. 5 28 From the foregoing data, it will be noted that, under We claim:

the comparable conditions shown, aqueous HBr desulfurized the stock 9 per cent and aqueous HC1, 28 per cent, while the extent of desulfurization obtained with aqueous HI was 73 per cent.

Example 22 1. A process for removing sulfur and oxygen from a hydrocarbon oil containing the same, which comprises contacting said oil at a temperature of at least about 550 F. but below a temperature at which substantial conversion of said oil to lighter products occurs with a reagent selected from the group consisting of iodine, hydrogen iodide, and an iodine-hydrogen iodide mixture.

2. A process for removing sulfur and oxygen from a hydrocarbon oil containing the same, which comprises contacting said oil at a temperature between about 650 F.

and about 750 F. with a reagent selectedrfrorn the group consisting of iodine, hydrogen iodide, and an iodinehydrogen iodide mixture.

3Q A process for desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting saidl oil with a reagent selected from the group consisting of iodine, hydrogen iodide, and iodine-hydrogen iodide mixtures at a temperature in excess of about 550 F. but below the cracking temperature of said oil, the ratio of gram atoms of iodine present in said reagent to the gram atoms of sulfur contained in said oil beingrat least about 0.1.

4. vA process for desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting said oil at a temperature between about 550 F. and about 850 F. with a reagent selected from the group consisting of iodine, hydrogen iodide, and an iodine-hydrogen iodide mixture' and present in such amountV that the ratio of gram atoms of iodine in said reagent to the gram atoms of sulfur contained in said oil is at least 0.1. f

5; A process-for desulfurizing, a sulfur-containing hydrocarbon oil, which comprises contacting said oil at a temperature between about 650 F. and about 750 F. with a reagent selected from the group consisting of iodine, hydrogen iodide, and an iodine-hydrogen iodide mixture and present in such amount that the ratio of gram atoms of iodine in said reagent to the gram atoms of sulfur contained in said oil is at least 0.1. Y 61 A processfor desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting said oil with a reagent selected from the group consisting of iodine, hydrogen iodide, and iodine-hydrogen iodide mixtures at atemperature between about 550 F. and about 850 F. for a period of between about 0.01 and about hours, the ratio of gram atoms of iodine present in said reagent to the gram vatoms Vof sulfur contained in said oil being between'about 0.1 andY about 2.5.

7; A process for desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting said oil with a reagent selected from the group consisting of iodine, hydrogen iodide, and iodine-hydrogen iodide mixtures at a temperature between about 650 F. and about 750 F. for a period of between about 2 and about 7 hours, the ratio of gram atoms of iodine present in said reagent to thegram atoms of sulfur contained in said oil being between about 0.1 and about 2.5.

8. A process for desulfurizing a sulfur-containing hy- Vdrocarbon oil, which comprises contacting said oilr at a temperature `between about 550 F. and the cracking ternperatureof the 'oil with a solution of iodine in hydrogen iodide, the ratio of total gram atomsof iodine to gram atoms of sulfur contained in said oil being at least about 9. A process for desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting said oil with a reagent selected from the group consisting of iodine, hydrogen iodide, and iodine-hydrogen iodide mixtures in the presence of hydrogen at a temperature in excess of about 550 F. but below the cracking temperature of said oil, the ratio of gram atoms of iodine present in said reagent to the gram atoms of sulfur contained in said oil being at least about 0.1.

10. A process for desulfurizing a sulfur-containing hydrocarbon oil, which comprises contacting said oil with a reagent selected from the group consisting of iodine, hydrogen iodide, and'iodine-hyd'rogen iodide mixtures in the presence of between about `and about 3000 p. s. i.g. of hydrogen at a temperature between about 650 F. and about 750 F., the Vratio-'of gram atoms of iodine present in said reagent to` the gram atoms of Y sulfur contained in said oil being at leastl about 0.1.

below a temperature atl whichV substantial conversion of said oii to lighter products occurs, with a reagent selected from thegroup consisting of iodine, hydrogen iodide, and iodine-hydrogen iodide mixtures, separating the resulting desulfurized oil from a residual iodine-containing tarry precipitate and recycling said tarryl precipitate for Vuse as the aforesaid reagent.

13. A continuous' process for desulfurizing a Sulfurcontaining hydrocarbon oil, which comprises contacting said oil at a temperature of at least about 550 F., but below a temperature at which substantial conversion of said-oil to lighter products occurs, with aqueous hydrogen iodide solution, separating the resulting liquid product consisting of a desulfurized oil layer and an aqueous layer containing dissolved lhydrogen iodide from a residual tarry precipitate, contacting said precipitate with water toremove an aqueous extract of hydrogen iodide therefrom,

separating the aforementioned desulfurized oil layer and aqueous layer, combining the latter with said aqueous extract andrecycling the resulting combined aqueous hydrogen iodide to contact with a charge of the original oil.

14. A continuous-process for desulfurizing a sulfurcontaining hydrocarbon oil, which comprises contacting said oil at a temperature of at least about 550 F., but below a temperature at which substantial conversion of said oil to lighter products occurs, with aqueous hydrogen iodide solution, separating the resulting liquid product consisting of a desulfurized oil layer and an aqueous layer containing dissolved hydrogen iodide from a residual tarry precipitate, Washing said precipitate with water to remove an aqueous extract of hydrogen iodide therefrom, heating the washed precipitate to ignition, recovering iodine vapors evolved therefrom, separating the aforementioned desulfurized oil layer and aqueous layer, combining the latter with said aqueous extract and recycling the resulting combined aqueous hydrogen iodide to contact with a charge of the-original oil.

References Cited in the file of this patent UNITED STATES PATENTS von Fuchs et al. oct. 3, 1939 

1. A PROCESS FOR REMOVING SULFUR AND OXYGEN FROM A HYDROCARBON OIL CONTAINING THE SAME, WHICH COMPRISES CONTACTING SAID OIL AT A TEMPERATURE OF AT LEAST ABOUT 550* F. BUT BELOW A TEMPERATURE AT WHICH SUBSTANTIAL 